Vacuum control unit



Feb. 27, 1968 D. e. GUETERSLOH ETAL 3,370,577.

VACUUM CONTROL UNIT Filed Nov. 10, 1965 HR mwE OSN TRG Y NE/ E W W /m 0 0 P w 6% A we AD N Y m B 1/ 4 4 r0 EJ Q 1 0 0 VJ A\Q 5 I 6 6 \Q 4 3 6 I O V I W 7 0O W 1 6 \w rfl M A I1 2 1 U4 6 Q0 4 2. Z M m z United States Patent 3,370,577 VACUUM ONTROL UNIT Donald G. Gnetersloh and Donald F. Wigner, Anderson, Ind, assignors to General Motors Corporation, Detroit, Mich, a corporation of Delaware Fiied Nov. 10, 1965, Ser. No. 597,087 6 Claims. (Cl. 123-99) ABSTRACT OF TIE DISCLOSURE A control valve is oppositely subjected to atmospheric pressure and induction vacuum. At a certain level of induction vacuum, a pilot valve closes an air inlet on one side of the control valve and a diaphragm opens the control valve to suddenly equalize the pressures. The resulting snap movement of the diaphragm provides full travel adjustment of ignition timing, and the pressure drop on the atmospheric side of the valve is simultaneously sensed to vary mixture ratio.

During certain periods of operation of internal combustion engines it becomes desirable to very rapidly change the ignition timing from one extreme of adjustment to another extreme. Contemporaneous with this change a variance in the combustible mixture in the carburetor is desirable to more efi'iciency operate the engine. Under these conditions of operation, in order to more completely take advantage of the ignition change, a mixture change should, therefore, take place.

It is an object of the present invention to provide an improved valve responsive to engine intake manifold vacuum to simultaneously change the timing of a vehicle engine and vary the mixture of fuel available thereto.

It is another object of the present invention to provide an improved valve selectively communicating atmospheric and vacuum pressure to an outlet from the valve.

It is still another object of the present invention to provide an improved vacuum responsive valve which responds to an initial buildup of vacuum pressure to cut olf atmospheric pressure communication between an inlet to the valve from the atmosphere and an outlet to a carburetor control valve and later simultaneously change the vehicle ignition timing and direct vacuum pressure to the outlet to the carburetor.

It is a further object of the present invention to carry out the aforementioned objects in a simple and economical manner.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a diagrammatical illustration of an internal combustion engine with the invention shown in its operative environment.

FIGURE 2 is a view taken along line 22 of FIG- URE 1.

FIGURE 3 is a sectional view of the subject invention taken along line 33 of FIGURE 2.

FIGURE 4 is a sectional view of the subject invention taken along line 44 of FIGURE 2.

Referring to FIGURE 1 an internal combustion engine generally designated by the numeral has a typical distributor 12 for controlling the ignition and a carburetor 14 for controlling the fuel air mixture to the engine. A valve generally designated by the numeral 16 has an output member 18 designed to change ignition timing and a vacuum responsive piston 19 designed to change the fuel air mixture in carburetor 14.

Referring to FIGURE 2 inlet 20 communicates with the intake manifold of engine 10 thereby providing a path for vacuum pressure communication to valve 16. Inlet 22 communicates atmospheric pressure from air cleaner 24 into valve 16 and outlet 26 is in pressure communication with piston 19.

Referring to FIGURE 3 inlet 20 is in pressure communication with a first chamber 28 through passage 30 and in communication with a third chamber 32 through passage 34. Second chamber 36 formed between the first chamber 28 and third chamber 32 is in fluid communication with outlet 26 through passage 38 and with inlet 22 through passage 40 formed on the right side of diaphragm 42 separating first chamber 23 into compartments i4 and 46.

A first valve means generally designated by the numeral 48 includes a diaphragm 50 movable translationally in third chamber 32 in response to changes of pressure therein. Diaphragm support 52 carries output member 18 and drive member 54. Drive member 54 is slidable in bore 56 formed between the third chamber 32 and the second chamber 36 and engages member 58 carrying sealing means 60. Sealing means 60- normally engages seat 62 and prevents free pressure communication between third chamber 32 and second chamber 36. Spring 64 bears against diaphragm support 52 biasing diaphragm 50 to the far right as viewed in FIGURE 2. Spring 66 bears against member 58 and assists spring 64 in maintaining diaphragm 50 at one extreme of translated movement.

A second valve means generally designated by numeral 68 includes a sealing member 70 movable in and out of engagement with seat 72 to selectively cut oil free pressure communication between compartment 46 and second chamber 36 through passage 74 when a certain vacuum pressure at inlet 20 is exceeded. Spring 76 bears against adjusting plug 78 and diaphragm 42 to normally maintain sealing member 70 away from seat 72.

In operation engine 10 is started which develops a vacuum pressure in the intake manifold. The vacuum pressure is freely communicated to inlet 20 of valve 16. This pressure is simultaneously communicated through passage 3-0 into the first chamber 28 and through passage 34 into the third chamber 32. At some predetermined point during engine operation the vacuum pressure in the first chamber 28 overcomes the force of spring 76 thereby shifting the second valve means 68 into a position wherein sealing member 70 sealingly engages seat 72.

Referring to FIGURE 4 it is seen that atmospheric pressure normally is communicated through inlet 22 through passage 40 into compartment 46 through passage 74 into second chamber 36. When sealing member 70 seats, this atmospheric pressure communication is cut off.

As engine intake manifold vacuum increases further at some predetermined point Which is established by the design of the particular engine involved, the vacuum pressure in the third chamber 32 overcomes the combined force of spring 66, spring 64, and the trapped atmospheric pressure in the second chamber 36. When diaphragm 50 moves initially, output rod 18 follows this movement and drive member 54 drives sealing means 60 from its seat at 62. Immediately upon the unseating of sealing member 60 the trapped pressure in chamber 36 is lowered by the communication of vacuum from third chamber 32 resulting in a very rapid shifting of diaphragm 50 to the left into an extreme of translational movement from the poised position shown in FIGURE 3.

As diaphragm 50 shifts to its extreme of movement, output rod 18 also moves and vacuum pressure is communicated into second chamber 36 through passage 38 to outlet 26. Therefore, vacuum pressure is immediately communicated to piston 19 of carburetor 14 to vary the fuel air ratio in accordance with the timing change brought about by the movement of output rod 18.

It is understood that the force of the springs 76, 66 and 64 will dictate the response points of the subject valve making the valve completely adaptable for use with engines requiring diiferent timing and mixture response levels. An important feature of the subject invention contributing to its utility is the contemporaneous actuation of a mixture control device with a timing change device thereby eliminating a delay common to rapidly shifting timing devices relative to related mixture controls.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. A valve for simultaneously driving an output member from one extreme of translational movement to another extreme of translational movement and directing vacuum pressure to a vacuum pressure operable device, said valve comprising: a valve housing having an inlet from a vacuum pressure source, an inlet from the atmosphere, and an outlet to a vacuum pressure operable device; a first chamber formed in said housing and having vacuum pressure communicated thereto from said vacuum pressure inlet; a second chamber formed in said housing and being in fluid communication with the inlet to said housing from the atmosphere and the outlet to the vacuum pressure operable device, a third chamber formed within said housing and being in fluid communication with said vacuum pressure inlet; first valve means including a diaphragm responding to pressure in said third chamber to establish fluid communication between said third chamber and said second chamber; and second valve means including a diaphragm positioned between said first and second chambers responding to pressure in said first chamber to cut off fluid communication between said second chamber and said inlet from the atmosphere, said first valve means including an output member shiftable between two extremes of translational movement in response to a vacuum pressure buildup in said third chamber to a predetermined level, said first valve means establishing vacuum pressure communication between said third chamber and said outlet to the vacuum pressure operable device at the same time that the output member of the first valve means shifts.

2. A valve according to claim 1 wherein the output member of said first valve means engages an ignition timing control and the vacuum pressure operable device is a piston in a carburetor positionable in accordance with the amount of change of ignition timing.

3. A valve according to claim 1 wherein said first valve means responds to a first level of vacuum pressurebuildup communicated from said vacuum inlet to shut oil atmospheric pressure communication between said inlet from the atmosphere and said second chamber to provide a path for vacuum pressure communication from said third chamber to said outlet to the vacuum pressure operable device upon the shifting of said first valve means.

4. A valve for instantaneously changing the ignition timing and simultaneously varying the fuel ratio of an engine in conformance with the change in timing, said valve comprising: a valve housing having an inlet from an engine intake manifold providing a vacuum pressure source, an inlet from the atmosphere, and an outlet to a vacuum responsive valve in the carburetor; a first chamber formed in said housing and having vacuum pressure communicated thereto from the intake manifold; a second chamber formed within said housing and being in fluid communication with the inlet from the atmosphere and in fluid communication with the outlet to the carburetor; a third chamber formed within said housing and being in fluid communication with the inlet from the intake manifold; first valve means including a diaphragm carrying an output member to an ignition timing device and a driving member for selectively establishing vacuum pressure communication between said third chamber and said second chamber, said diaphragm being translationally movable between two extremes of movement wherein the output member to the ignition timing device moves between extreme positions corresponding to extremes of ignition tuning; and second valve means forming two pressurizable compartments in said first chamber, a first of said compartments being normally under vacuum-pressure and a second of said compartments being normally under atmospheric pressure, said second valve means being shiftable to shut oif atmospheric pressure communication between the atmospheric inlet and said second chamber in response to vacuum pressure buildup to 'a first level, said first valve means being shiftable into position wherein said ignition timing device is altered into a full range of adjustment and vacuum pressure is simultaneously communicated to the carburetor in response to a vacuum pressure buildup at said inlet from the intake manifold to a second predetermined level.

5. A valve according to claim 4 wherein said first valve means is biased against vacuum pressure by a plurality of spring means and by atmospheric pressure communicated to one side thereof from said second chamber, said first valve means being biased toward an open position by atmospheric pressure communication to one sideof said diaphragm and vacuum pressure communicated to an opposite side of said diaphragm.

6. A valve according to claim 4 wherein said second valve means responds to a buildup of vacuum pressure to a first predetermined level to shut off atmospheric pressure communication from the inlet to the valve housing from the atmosphere and said second chamber, said first valve means being thereby adapted to be quickly shiftable to an extreme of movement from a poised position when vacuum pressure buildup to a said predetermined level shifts said first valve means to an initial open position from the normally closed position of said first valve means.

References Cited UNITED STATES PATENTS 3,027,884 4/1962 Bale 123ll7.l

RALPH D. BLAKESLEE, Primary Examiner. 

